1. Technical Field
The present disclosure relates to a biomedical snap electrode and method of manufacturing a biomedical snap electrode for delivering electrical current to a subject. More particularly, a biomedical snap electrode and method of manufacturing a biomedical snap electrode for electrical stimulation of muscle tissue or nerves is disclosed.
2. Description of the Related Art
Medical snap electrodes are well known in the medical field for use in measuring and monitoring the condition of a subject by interpreting various types of electrical signals monitored through the skin of the subject. Some well known applications which use medical snap electrodes include electrocardiography and electroencephalography. In those applications small signals are received though electrodes that are attached to the subject's skin. A lead wire provides a connection between the electrode and the monitoring equipment, which amplifies and displays or interprets the small signal.
Other well known applications of snap electrodes include electrical muscle stimulation (EMS), transcutaneous electrical nerve stimulation (TENS) and biofeedback. In EMS and TENS applications, for example, electrical current is applied through the skin to stimulate a subject's muscles for therapeutic purposes or nerves for pain reduction purposes and for physical training.
One commonly used method for fabricating a snap electrode by attaching a snap assembly into a stimulating electrode is described with reference to FIG. 1. A conductive top snap 10 and a conductive bottom snap 12 designed to mate with the top snap 10 are pressed together to secure the bottom snap 12 against a conductive layer 14 and to secure the top snap 10 against a cover layer 16 on the electrode. The conductive top snap 10 is typically made from metal and the conductive bottom snap 12 is typically made from metal or plastic with a conductive layer deposited thereon. The conductive layer 14 can be a conductive film or a layer of thin metal such as aluminum or tin, for example. The cover layer is typically made from a non-conductive material such as polypropylenes, polyethylene, polyurethane or other flexible material.
When the top snap 10 and bottom snap 12 are pressed together, portions of the bottom snap 12 make electrical contact with portions of the top snap 10 by at least partially penetrating the conducive layer 14 and the cover layer 16. An electrical connection is thereby made between the bottom and top snap. The electrical current flow for an electrode using this construction follows a path from a stimulating device (not shown) to a lead wire (not shown) to the top snap 10 to the bottom snap 12 and then to the conductive layer 14. A conductive gel (not shown) is usually applied to the bottom surface 15 of the conductive layer 14 to improve electrical contact with an area of a subject's skin.
Another commonly used method for fabricating a snap electrode is described with reference to FIG. 2. A conductive top snap 18 and a non-conductive bottom snap 20 designed to mate with the top snap 18 are pressed together to secure the bottom snap 20 against a conductive layer 22 and to secure the top snap 18 against a cover layer 24 on the electrode. The conductive top snap 18 is typically made from metal and the non-conductive bottom snap 20 is typically made from plastic. The conductive layer 22 is typically a conductive film or a layer of thin metal such as aluminum or tin. The cover layer 24 is typically made from a non-conductive material such as polypropylenes, polyethylene, polyurethane or other flexible material.
In snap electrodes that are assembled using the method described with reference to FIG. 2, an opening 26 larger than the snap is cut through the cover layer 24 to allow the top snap 18 to rest directly on the conductive layer 22. The electrical current flow for an electrode using this construction follows a path from a stimulating device (not shown) to a lead wire (not shown) to the top snap 18 to the conductive layer 22. A conductive gel (not shown) is typically applied to the bottom surface 28 of the conductive layer 22 to improve electrical contact with an area of a subject's skin.
In some cases, applications of electrical energy to a subject for EMS and/or measurement of electrical signals causes some apprehension due to the subject's perception that the electrode can burn or otherwise cause discomfort to the subject. Such apprehension can be enhanced when a snap connector is visible by viewing the bottom surface of an electrode which contact's the subject's skin. Each of the commonly used methods of constructing electrodes described above with reference to FIG. 1 and FIG. 2 include visible snaps on their bottom surface. Even though any substantial heating of the electrode or snaps is highly unlikely, it can be envisioned that a defective conductive layer could potentially cause a hot spot touching the patient's of the skin. Accordingly, many patients and/or practitioners avoid use of appropriate medical electrodes. It would therefore be desirable to provide a medical snap electrode that prevents viewing of a snap through the conductive layer of the electrode to reduce apprehension of burning or discomfort.